SU605168A1 - Ultrasonic pulse-echo flaw detector - Google Patents

Description

coincidence, the inputs of counters b, 8 and 10 are connected to the output of the synchronizer.

Ultrasonic echo pulse flaw detector works as follows.

The synchronizer 1 starts the generator 2, which excites the piezoelectric transducer 3, emitting signals into the controlled product.

The signals reflected from defects and surfaces of the product under test are fed to amplifier 4, from the output of which pulses through cascade 5 of coincidence arrive at the input of counter 6. From the output of counter, pulses go to cascade 7 of coincidence, on which the duration of pulses

  s + t

where TI is the duration between the first and second reflected pulses; T2 - the duration between the second and third reflected pulses; tz - the duration between the third reflected pulse and the sync pulse

.

The falling edge of pulse T closes the coincidence stage 5.

The pulses TI and ta-bc are fed to the inputs of the reversible counter 8, to the other input of which pulses are received from the generator 14 of the pulses through a cascade 13 coincidence. This generator operates for + + T2 time, providing a discrete comparison of the time intervals TI and T2, while the reversible counter 8 is filled during the time T in the addition mode. After the operation of adding the number of pulses n that fill the interval TI, the reversible counter for the time T2 operates in the subtraction mode.

After completion of the subtraction, two cases are possible: when the difference is positive, the defect is located in the subsurface control zone, when the difference is negative, the defect is located in the bottom zone of the contral.

In the first case, the subtraction permission continues until the counter is reset to zero, and from the end of the duration n to

resetting the counter to zero, the difference of the pulses "1-tiz through the cascade 9 coincidence goes to the counter 10.

In the second case, from the moment the counter transitions to zero state until the end of the duration T2, the difference L2-Hi through the stage 9 of coincidence enters the counter 10.

Thus, the absolute value of the difference in the number of pulses arrives at counter 10.

(nj- “a).

When this difference is exceeded on the decimator 11, an impulse is received on the indicator fixing the defects. All counters are reset to zero by synchronizer 1.

The described flaw detector allows reducing uncontrolled near-surface and near-bottom areas of the product, increasing the reliability of the control.

Claims (1)

Invention Formula An ultrasonic echo pulse flaw detector containing a series-connected synchronizer, a probe pulse generator, a piezo transducer, and an amplifier, as well as an indicator characterized in that, in order to increase the reliability of the control, it is provided with series-connected first cascade of coincidence, whose input is connected to the amplifier output, first counter, second coincidence cascade, second reversible counter, third cascade of coincidence, third counter and decoder, the output of which is connected to the indicator input the fourth cascade of coincidence, the output of which is connected to the second input a reversible counter, the first input to the output of the last, a pulse generator whose output is connected to the second inputs of the third and fourth stages of the match, and the input to the second input of the first stage of the match and the second output of the second stage of the match, the other two outputs are connected to the corresponding inputs of the third cascade match, the inputs of the meters are connected to the output of the synchronizer.